Free piston machine



July 15, 1941.`

FREE PISTON MACHINE Original Filedieb; 16, 1939 2 SheetsfSheet 1 July 15, 1941. R. PATERAs PESCARA FREE VPIsToN MACHINE riginalfiled Feb. 16, 193,9

2 Sheets-Sheet 2 inve/vrai?. 'A @am Paz-Enns Pesca/llrakwsys Patented July 15, 1941 2,249,397 Fries Y FREE PIsToN MACHINE Raul Pateras Pescara, Neuilly sur Seine, France,

assignor of three-tenths to Societe dEtudes et de Participations Eau, Gaz, Electricite, Energie S. A., Geneva, Switzerland, a society oi' Switzerland Original application 'February' 16,v 1939, Serial No.

256,751. Divided and this application February 26, 1940, Serial No. 320,950. In Luxemburg February 19, 1938 6 Claims.

The present application is a division of my copending application Serial No. 256,751 of February 16, 1939.

The invention relatesto mechanisms for synchronizing the oppositely-reciprocating piston groups of a free piston machine, the pistons of which can have variable strokes.

It is known to connect the said reciprocating groups which are to be synchronized to the ends of oscillating levers by simple connecting rods, the levers generally being disposed on either side of the machine and being parallel in direction or crossed,

During the working of the machine, however, such structure produces inertia forces directed transverse to the direction of the'displacements of the reciprocating groups, and, in the case of a machine provided with oscillating levers parallel to each other,'creating an alternating torque which tends to produce an oscillation of the machine abouta transverse axis. In the case of a machine having crossed oscillating levers, instantaneous torques are produced which tend to rotate the reciprocating groups about their axis.

The chief object of the present invention is to provide amechanism of the type above described which is better adapted to meet the requirements of practice than present similar mechanisms and, in particular, free from the disadvantages above set forth. According tothe present invention, it consists of a kinematic mechanism, wherein the reactions transverse and particularly normal to the path of movements of the reciprocating parts are transmitted to a least one rigid element arranged in (Ci. 114-110)l ing mechanisms arranged on either side of the machine. This particularly permits the disturb? such manner as to be subjected simultaneously to the reactions of opposed direction, so as to balance them on said element.

Other features of the presentv invention will appear from the following detailed description of some specific embodiments thereof.

Preferred embodiments of the present invention will be described hereinafter, with reference tion of some of the elements of the synchronia` ing mechanism of Fig. 2. Y

In the renewing description, the invention will Amade in any suitable conventionalmanner. For

instance, as shown in Fig. 1, the machine is a motor-compressor including two motor pistons I and 'I' adapted to slide in a cylinder 2, the wall of which is provided with inlet ports 3 and outlet ports 4 which are opened, respectively, by the pistons I and I', when the latter are moving near to the ends of their outward strokes. Compressor pistons 5 and 5', respectively rigid with the pistons I and I', are adapted to coact with com pressor cylinders each provided ywith suction valves 6 or 6' and discharge valves i or 'I'.

According to the invention, the means for synchronizing the displacements, in opposite direc-y tions, of the reciprocating parts or piston groups of the machine are arranged so that the normal reactions are transmitted to elements connected to the movable parts oi said synchronizing means in such a manner tl at said elements are subjected to forces of equal intensitiesv but opposed in direction so that they absorb these forces. l

Referring to Fig. 1, the structure is devised in such manner'that. e normal reactions are balanced independently for each of the synchronizing eiects of these reactions to be eliminated, both when the synchronizing oscillating levers are parallel and when they are crossed.

In this embodiment of the invention, the displacements of the reciprocating parts of the machine are combined, in the'known manner, by means of oscillating levers I8 which pivot about a fixed axis 0 and may either be parallel or crossed. The ends of these levers are connected to the reciprocating piston groups of the machine through connecting rods such as shown at I9 and I9' for the oscillating lever I8. It will be understood that only the parts on one side of the machine are shown in Fig. l.

The pivots 20 and20' of the connecting rods I9 and I9' located on the reciprocating pistons of the machine'are connected', respectively, through connecting rods 2i and 2|', to the ends of bell crank levers 22 and 22', mounted on xed pivots 23 and 23'. The other ends of the bell crank levers 22 and 22 are linked, through rods 24 and 24' to toothed sectors 25 and 25? pivoted about fixed pivots 28 and 26' and having their respective teeth in mesh.

The various elementsy of this mechanism are arranged in such manner that the normal re.- actions R and R' (which are always in opposed directions) tend to turn the toothed sectors 25 and 25' in the same clockwise direction, so that the teeth of said sectors, being subjected to opposed forces of equal intensities, absorb these forces.

It will be readily understood that, when proceeding in the same manner for the pivoting systems located on the other side of the machine, a synchronizing device is obtained with which the reactions normal to the direction of the piston arrangements are transmitted to tlxed elements, i. e. the toothed sectors in this case, so that they compensate one another and are thus eliminated.

The further embodiment which is illustrated by Fig. 2 concerns more particularly the case in which the synchronizing oscillating levers I9 and |81 are crossed. The device is arranged in such manner as to transmit to rigid elements capable of absorbing them, preferably by their resistance to twisting, the reactions of opposed directions which tend to produce rotations of the reciprocating parts of the machine about their axis. These reactions are reactions R and R1 and reactions R' and R'1 which, in consequence of this arrangement, become forces which compensate each other.

According to this 'particular embodiment of the invention, the reciprocating parts of the machine to be synchronized are connected to oscillating levers I9 and |81, respectively, through connecting rods I9, I9' and |91, I91. The conl nectingA rods corresponding to a reciprocating;

part of the machine may be pivoted either to the end of rods 21. and 211 rigid with the corresponding compressor piston, as shown on the left hand side of Fig. 2 or to the ends of a transverse bridge part 28', as shown on the right hand side of the figure.

The pivots of the connecting rods corresponding to the reciprocating part of the machine on the left of Fig. 2 are connected to an oscillating transverse bar 29 by rods 39 and 301. The pivots of the other connecting rods are connected to an oscillating transverse bar 29' by rods 30' and 30'1, the rods 30, 301 and 99', 391 being respectively connected to crank arms 3i, SI1, and Il',

bar 29 and the others by the bar 29'. f

It will be readily understood that the reactions R and R1 act on the bar 29 with opposed `directions of rotation and that the bar will absorb said reactions by twisting. The same is true concerning the bar 29' and the reactions R' and R1.

Taking advantage of the nxing of the axes oi' the bars 29 and 29', it is possible to make use of the bars for introducing a cooling uid or a hbiricant into the reciprocating parts oi the ma- C ne.

In particular, whenthe synchronizing connecting rods are pivoted to a bridge 2l' rigid with a reciprocating part of the machine, the arrangement illustrated by Fig. 3 may be used.

In this arrangement, a conduit 92 for lthe feeding of a fluid such, for instance. as the cooling liquid, and a conduit 99 for the outflow oi this liquid are respectively connected to the ends of the bar 29'.

'In the bar 29', in the rods 39' and 991, in the bridge piece 29' and in the reciprocating part in question, conduits 34 are provided which provide a circuit through whichv the cooling liquid can flow, packing means, such as shown at ll, being provided at the various joints of the mechanisms through which this circuit passes.

from the above description to make it unnecessary to enter into further explanations.

lli, the iirst of which are -rigidly carried by the should be well understood that the invention is not limited thereto as there might be changes in the arrangement, disposition and form* of the parts without departing from the principle of the present invention as comprehended within the scope of the appended claims.

What I claim is:

l. In a machine including a frame and twoV parts reciprocating in opposed directions along a common longitudinal axis of movement with respect to saidvframe, a synchronizing device for synchronizing the opposite movements of said parts which comprises kinematic transmission means carried by said frame and interposed between said reciprocating parts. said synchronizing device producing opposed reactions transverse to said axis, at least one rigid member carried `by said frame, and means separate from said transmission means for transmitting to said rigid lmember the opposed reactions.

2. In a machine including a frame and two parts reciprocating'in opposed directions along a common longitudinal axis of movement with respect to said frame, a synchronizing device which comprises, in combination, at least one parallel lever pivoted to said frame about an axis lperpendicular to said longitudinal axis, connecting rods extending between said reciprocating parts and the respective ends of said lever, two

toothed elements rotatably carried by said framel and meshing together, and means for transmitting to said rotatable elements, respectively, the opposed reactions transverse to said axis, due to said synchronizing device.-

3. A device according to claim 2 in which said rotatable members consist o! toothed sectors operatively connected to said reciprocating parts.

4.-In a machine including a frame and two parts reciprocating in opposed directions along a common longitudinal axis o! movement with respect to said frame, a synchronizing device which comprises, in combination, two crossed levers pivoted to said :frame on either side thereof about a common axis perpendicular tosaid longitudinal axis. connecting rods extending between said reciprocating parts and the respective ends of said levers, two bars Journalled in said frame levers, and connecting rods interposed between said crank arms and the reciprocating parts for transmitting to each of said bars opposed tor sional stresses which are absorbed by said bar.

5. A device according to claim 4, in which said bars, -crank arms and the last mentioned connecting rods are hollow so as to constitute conduits for a circulating iiuid.

6. In a machine as claimed in claim l, said kinematic transmission means comprising a lever pivoted about a xed axis, and links connected to opposite ends of said lever and to said two parts.

, RAUL PATERAS PElCARA.l 

